Synthesis of benzyl bromides with hexabromoacetone: an alternative path to drug intermediates

A series of benzyl bromides were efficiently prepared from the corresponding alcohols with Br₃CCOCBr₃/PPh₃ at low temperatures and under neutral conditions. The present protocol was applied to the heterocyclic analogues and to the successful synthesis of the precursor of the antiulcer drug omeprazole, thus furnishing an alternate, mild method for the preparation of these drug intermediates. A significant steric factor was observed throughout both series supporting a S_N2 mechanism.